Follow-up to PR 52804, applying thaJeztah's review suggestion: check
IsLoopback first for both address families (preserving any requested
loopback address), and only fall back to the canonical loopback for
the family otherwise. No behavior change; ::1 now returns through the
loopback-preserving branch instead of the IPv6 fallback, with the same
result.
Signed-off-by: Andrew Liu <andrewjliu22@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
In rootless mode, ChildHostIP maps every IPv4 host address to 127.0.0.1
in the child network namespace. Port bindings on the same port but
distinct loopback addresses (e.g. 127.0.1.2:80 and 127.0.1.3:80) were
therefore both reserved as 127.0.0.1:80 by the port allocator in the
child namespace, and the second binding failed with "Bind for
127.0.0.1:8080 failed: port is already allocated" even though the
requested addresses do not conflict.
Preserve IPv4 loopback host addresses as the child host IP instead. The
child namespace's lo interface covers all of 127.0.0.0/8, so the
addresses are bindable as-is, and RootlessKit's builtin port driver
both listens on the requested parent address and dials the requested
child address verbatim. Port drivers that disallow loopback child IPs
(slirp4netns) are unaffected: their forced non-loopback childIP is
selected before the loopback fallback.
Signed-off-by: Andrew Liu <andrewjliu22@gmail.com>
